38 HISTORY OF ELECTRICITY. 



as settled. For, in reality, if we assume, as ,/Epinus 

 does, the mutual repulsion of all the particles of 

 matter, in addition to the repulsion of the particles 

 of the. electric fluid for one another and their 

 attraction for the particles of matter, the one fluid 

 of ./Epinus will give exactly the same results as the 

 two fluids of Coulomb. The mathematical formulae 

 of Coulomb and of Poisson express the conditions 

 of the one case as well as of the other ; the inter- 

 pretation only being somewhat different. The place 

 of the forces of the resinous fluid is supplied by 

 the excess of the forces ascribed to the matter 

 above the forces of the fluid, in the parts where 

 the electric fluid is deficient. 



The obvious argument against this hypothesis 

 is, that we ascribe to the particles of matter a 

 mutual repulsion, in addition to the mutual attrac- 

 tion of universal gravitation, and that this appears 

 incongruous. Accordingly, jEpinus says, that when 

 he was first driven to this proposition it horrified 

 him 15 . But we may answer it in this way very 

 satisfactorily : If we suppose the mutual repulsion 

 of matter to be somewhat less than the mutual 

 attraction of matter and electric fluid, it will follow, 

 as a consequence of the hypothesis, that besides 

 all obvious electrical action, the particles of matter 

 would attract each other with forces varying in- 

 versely as the square of the distance. Thus gra- 



15 Neque diffiteor cum ipsa se mihi offerret me ad 



ipsam quodammodo exhorruisse. Tentamen Theor. Elect, p. 39. 



